Exemplary embodiments of the present invention relate to a fuel filter and method for the removal of sulfur containing compounds from a post-refinery fuel stream more particularly exemplary embodiments relate to a fuel filter and method for the removal of sulfur containing compounds wherein the filter provides an additive to the fuel.
There continues to be environmental concern relating to air pollution stemming from use of internal combustion engines, especially those used in transportation applications such as cars, trucks, boats and the like, and stationary power sources such as diesel generators and the like. In addition to being a direct source of pollution in the form of SOx, sulfur also poisons the catalytic surface of exhaust after treatment devices. By reducing sulfur in the fuel and therefore the exhaust, the useful life of exhaust after treatment devices is extended. In addition, and since many internal combustion engines employ an exhaust gas recirculation system there is also a desire to remove the sulfur from the exhaust gas.
New power sources such as fuel cells will also require fuel streams to have similar or lower levels of sulfur. Fuel cells burn hydrogen that has been reformed from various hydrocarbon fuels, such as gasoline. Sulfur will poison the active surfaces of the fuel cell, thus shortening its life.
As a result, various governments and regulatory bodies continue to enact legislation intended to substantially lower the acceptable levels of sulfur and sulfur containing compounds present in the fuels used in internal combustion engines.
The U.S. EPA, for instance, has enacted regulations requiring diesel fuel producers to phase in the production of low sulfur diesel fuel (equal to or less than 15 ppm sulfur) beginning in 2006 and ending in 2010. Similarly, from 2004 to 2006, gasoline sulfur levels were reduced from 50 ppm to 30 ppm. The need for commercially available fuels having continually lower levels of sulfur containing compounds creates new problems for manufacturers of such fuels, i.e., the refining industry.
The introduction of low-sulfur diesel fuels has also caused problems with fuel-injection equipment because the fuel's lubricating properties were reduced by the hydrotreating process needed to lower the sulfur content. The majority of the fuel-lubricated distributor injection pumps for passenger cars and small trucks showed increase wear if the low-sulfur diesel fuel is not treated with lubricant additives. Increased wear reduced the injection pump's service life and caused engine power loss, higher emissions, and fuel consumption, poor driveability, and difficulties when starting.
Adding lubrication additives to the diesel fuels appears to be the only viable solution for overcoming the aforementioned problems.
Additionally, there are issues with the incompatibilities with additized diesel fuel in pipelines when a jet-fuel is also transported in the same pipelines. Consequently additization will have to be done after the fuel is distributed and after the refinery.
Furthermore and since the refined diesel fuel still has some sulfur in it there is a desire to provide a fuel filter in the system of an internal combustion engine or other device wherein the fuel filter is configured to further reduce the sulfur content of the fuel. For example, one approach for removing the sulfur from the fuel is to place an adsorbant in a filter positioned to filter the fuel stream however, these adsorbants may also filter out desired properties or additives of the fuel namely, lubrication additives which were added to the fuel to address the aforementioned issues associated with low sulfur diesel fuels.
Accordingly, it is desirable to provide a fuel filter that delivers lubricating additives to the fuel.